BP 79

It became a headache when an Oni evolved into a Gon. This was because Gon developed a keen sense of smell for ability users. If there were only humans, they would slaughter them incessantly, but if they were mixed with ability users, the story changed. They would first find the Esper, tear them to pieces, and then find the Guide to drink their blood. With their strengthened bodies, they repeated this behavior until their own lives ended. They were an atrocious and cruel breed.

The appearance of Oni, the evolution of Gon. An already erratic situation was changing rapidly before they could even react. Belatedly, the alarm began to wail. The alarm echoed eerily, like the scream of someone already dead.

There were various alarms for when monsters appeared, and the one sounding now was the signal for an OniCube, the most dangerous state.